Handbags and accessories retailers Kipling USA’s e-commerce site kipling-usa.com increased its average mobile load time by 1.5 seconds in February, making it one of the slowest mobile sites on the February mobile site index, according to data provided by digital performance analytics company Catchpoint Systems Inc.

Internet Retailer and Catchpoint Systems produce two monthly site performance indexes, one for mobile sites and one for desktop sites, ranking the 10 fastest retailers among the top 100 retailers in the Internet Retailer 2016 Top 500 Guide.

The top 10 fastest mobile sites were mostly consistent from February to January, and so Catchpoint Systems dug into why some retailers rank at the bottom of the index.

Kipling USA is owned by apparel manufacture VF Corp., No. 92 in the 2016 Top 500 Guide. During Feb. 13-26, the mobile site home page on average loaded in 6.61 seconds compared with 5.12 seconds in last month’s mobile index.

The slower load time stemmed from the retailer increasing its mobile home page size to a whopping 7.76 megabytes from 2.96 megabytes the previous month. For comparison, the average mobile home page weight for the top 100 retailers on the February index is 2.04 megabytes. The retailer added new images to its website during the last week of January, which is why the page weight increased, Catchpoint Systems says. The number of images jumped to more than 150 from less than 50 images the previous month, according to Catchpoint data. Kipling did not respond to a request for comment.

Similarly, general merchandise retailer Fingerhut.com had one of the slowest load times. Fingerhut is part of Bluestem Brands Inc. (No. 41), which is the parent company to 15 e-commerce brands such as women’s clothing retailers Drapers and Damons and Appleseeds.

Fingerhut on average loaded in 7.16 seconds, placing it at the bottom of the index, even though this speed is a two second improvement from last month’s average load time of 9.17 seconds. While Fingerhut’s 2.52 megabyte mobile home page size contributes to its slow load time, it is not the main cause, Catchpoint says. Rather, it’s the retailer’s above average number of hosts, at 98, and items on the page, at 349, that are the biggest contributor, the vendor says.

“When we compare websites with page size above 3 megabytes, we see that the heavier sites are faster in comparison to Fingerhut,” a Catchpoint spokesman says. “The only difference between these sites is the number of hosts and items on the page which are much lower than that of Fingerhut.” The retailer did not respond to a request for comment.

For the two weeks of Feb. 13-26, the average mobile home page load time for the 100 retailers was 3.17 seconds compared with 3.32 seconds during the two week period Jan. 16-29. The average page weight for the 100 retailers was 2.04 megabytes compared with 1.93 megabytes, and the average number of hosts was 45 compared with 44 the previous month. The average number of items was 142 compared with 137 in January. The top 100 e-retailers’ mobile sites were, on average, 99.55% available for the February mobile index compared with 99.86% available for the January index.

Catchpoint Systems monitors each website’s home page with measurements taken from Catchpoint Systems’ in-country or in-region monitoring nodes, at intervals of five minutes for two weeks each month. Backbone monitoring nodes are the locations of Catchpoint’s devices that are near data centers operated by the main Internet Service Providers that provide service to a city. The nodes simulate end-user contact with each website. Catchpoint monitors webpage load time, availability, hosts and items. They are defined as follows:

Web page load time: The time it takes for enough page elements to load for a consumer to begin interacting with a page, such as searching, tapping or scrolling. From a consumer point of view, it’s the time it takes for the progress bar or spinning wheel to stop.

Availability: The percentage of time during the test week that the site can be successfully reached by a consumer.

Host: Any domain that delivers data, content or services over the internet to the site.

Items: Also known as requests. Webpage components, such as files or images that a page loads from internal and external hosts or domains. These can include PDFs, PNGs, JPEGs and GIFs.